I'm somewhat familiar with McCabe style complexity measures[1], but I'm curious if there's a metric that measures a code base's ease with which it can be refact

I'm somewhat familiar with McCabe style complexity measures[1], but I'm curious if there's a metric that measures a code base's ease with which it can be refactored or extended. Has anyone heard of such a thing? [1]: https://en.wikipedia.org/wiki/Cyclomatic_complexity https://en.wikipedia.org/wiki/Cyclomatic_complexity